Hello All,
I'm new to plants and I'm having some issues. I started putting some live plants (not sure what type) into my 5g betta tank about a month ago. Those plants are doing fantastic. then i read that you are supposed to quareantine plants for 2 weeks so I starts to do that. I have a 5 gallon QT setup and I put 3 new plants in about 1.5 weeks ago. Problem is that they are not doing well. Several of the leafs are almost mealted and or dying. I dont know what type they are as the fish store people can never identify them. I have pictures below (you can see the spots on the leafs in one picture and the others are browning)..... what is going on?

I have a 5g non-heated QT tank. Sponge filter and I put liquid fertilizer (1ml) every other day. 23 watt blub, stays on about 8hours.

On your second picture the plant floating on top is Anacharis . I have two of these in my 5 gallon and they have new growth on them but on one the leaves are looking a little brown almost clear looking, but the top of it has a new stem growing so it must be doing fairly well so I am just keeping and eye on it and if the leaves on the bottom start looking like they are dieing I guess just pull those off. The other stem is doing great still really green and long stem of new growth that is growing over night like a weed. I am new at water plants too so just learning by reading the posts here.

I dont know what the other plants are but good luck with them wish I could be of more help.